Shear wave velocity inversion based on Scholte waves for a fully saturated seabed

Abstract

As a non-destructive and convenient method, Scholte waves inversion method has been widely used in various engineering applications. However, previous inversion methods treated the seabed sediments as a fully elastic medium, and ignored the porous nature of the sediment. In this paper, a state-of-art inversion model of shear wave velocity, which takes into account the porous property of the seabed, is established based on Bloch's theorems and Biot's theory. Then, the validity of the results is established and the influences of porosity and permeability coefficient of seabed soil are discussed in detail. Finally, an inversion platform using a Python environment is built, and Differential Evolution algorithm and Bayesian approach are employed to obtain the shear velocity profile of the seafloor in the northern North Sea. The calculated results based on the proposed model are highly consistent with the in-situ measurements in the shallow seabed compared to those calculated by the elastic model. This suggests that the influence of porous medium properties on shear wave velocity should be carefully considered for more accurate marine geological surveys.